Fig. 5.

Sgk2 mRNA is not regulated by aldosterone in rat kidney homogenates or in rat kidney sections. A: Northern blot analysis for sgk2 mRNA in kidney homogenates of adrenalectomized rats injected subcutaneously with aldosterone. Male rats were pretreated with 10 μg RU486 for 30 min before aldosterone was injected (1 μg/100 g body wt). Kidneys were harvested from each rat (n = 5–8/group) at 2 (2h) and 4 (4h) h after aldosterone injection. Blots were hybridized with probes for sgk2 and sgk1 mRNA to assess respective levels in kidney homogenates. Cyclophilin mRNA served as RNA loading controls. The blot shown is representative of 3 independent experiments. S, sham operated; Adx, adrenalectomized. B: sgk2 mRNA expression by radioisotopic in situ hybridization of kidneys from adrenalectomized rats treated with RU486 and graded doses of aldosterone (0.1–3 μg/100 g body wt). Autoradiograms of whole rat kidneys harvested 2 h after aldosterone injection. No change in sgk2 expression is apparent in any part of the kidney in response to aldosterone treatment. Four sections per animal (n = 5–8/group) were analyzed. C: autoradiograms of whole rat kidneys show robust induction of sgk1 by aldosterone treatment (2 h) in the cortex, and, more generally, in the medulla.